There are many different downhole tools in the oil and gas industry which require that a seal be established in the annulus between a fluid transmission conduit or tubing string disposed in a well bore and the outer well casing. These tools may relate to the drilling and completion of the well, the production of the well, the servicing of the well, or the abandonment of the well. In addition to conventional packers, polished bore receptacle (PBR) packoffs have also been used to isolate the production-tubing conduit or setting tools from the annulus. Current PBR packoffs typically include a seal member formed from plastics and rubbers. However, plastics and rubbers are prone to wear caused by high temperature, high pressure, and corrosive environments such as found in the oil and gas industry. Accordingly, seals formed from plastics and rubbers may experience a limited service life or are restricted from certain service environments. Furthermore, the large friction between plastic or rubber seals and PBR bore requires large setting force, which can increase the operating costs as well as roll-over failures. Thus the industry would be receptive to new packoffs having improved wear-resistant and lubrication properties.